The father of the house might call himself King over the home and we get what he’s saying. In the home, Dad’s Rule reigns. How far will Husband get with Wifey if he says “Woman, I am King in this house”?
Or what about the teenager who has on the door of his room “King of My Castle”: weird thing to have a King who has authority over a room in a house that isn’t his. A King without a Kingdom is a strange thing.
Christ is not a King without a Kingdom. He outright says that his Kingdom is not of this present world (John 18:36). But more so, his Kingdom is one that is everlasting (Dan 2:44; Luke 1:33), is righteous (Ps 45:6; Heb 1:8-10; Isa 32:1; Jer 23:5), in which all the saints are subject to Him (Col 1:13).
For he has rescued us from the dominion of darkness and brought us into the kingdom of the Son he loves
Jesus has an overarching eternal kingdom.